Showerproof coat for petite ladies (under 5'4)

Can anyone recommend one? I need to buy one quick as the weather here has really turned. I struggle to find coats that fit off the peg as they're usually way too long in body and sleeve (I'm looking at you Sea Salt Janelle!) - would like it to be mid thigh though at least and at least showerproof to cope with a 2 minute school run dash.